Spike Lee has heavily criticised Donald Trump for his response to the violent events that took place at the white supremacist march in Charlottesville, Virginia last year, which the director described as a “blemish on America”.

Lee’s new film, BlacKkKlansman, is adapted from the memoir of Ron Stallworth, an African-American police officer who infiltrated a chapter of the Ku Klux Klan in the 1970s by using a white double. In the final moments of the film, the drama segues into real-life video from Charlottesville, culminating in the footage of white supremacist James Fields ploughing a car into protesters, killing activist Heather Heyer and injuring dozens of others.

Speaking at a press conference for BlacKkKlansman at the Cannes film festival, Lee said that the film was already completed when he first witnessed news of the events from Charlottesville, but knew the footage needed to appear in the film “right away” and asked the permission of Heyer’s mother, Susan Bro, to use the footage.

Adam Driver and John David Washington in BlacKkKlansman

“I was not going to put that murder scene in the film without her blessing,” Lee said. “And Mrs Bro said, ‘Spike, I give you permission to put that in.’ So once I got permission I said, ‘Fuck everyone else, that motherfucking scene is staying in the motherfucking movie.’ Because that was a murder. Heather should be alive now.”

Lee then pivoted to Trump’s response to the march, and the President’s suggestion that there were “very fine people on both sides” in attendance at Charlottesville.

“We have a guy in the White House – I’m not going to even say his fucking name – who in the defining moment, not just for Americans but for the world [who] was given a chance to say: ‘We are about love and not hate,’” Lee said. “And that motherfucker did not denounce the motherfucking clan, the alt-right and those Nazi motherfuckers. He could have said to the world: ‘We are better than that’.”

BlacKkKlansman, which received its premiere at the festival on Monday, has been received positively by critics, and currently holds a 100% rating on Rotten Tomatoes. Despite this, Lee said that he wasn’t concerned about positive or negative reviews for the film. “I know my heart, I don’t care what the critics say or anybody else, but we are on the right side of history with this film,” he said.